Plastic bonded first fire

ABSTRACT

An improved method of assembly and first fire means for use in munitions; the improvement being a first fire structure having the particles of an oxidizing material, such as potassium chlorate, bonded together by a polymer produced by a reaction between a thioepoxy resin and a mercapton. The bonding is accomplished by mixing the oxidizer, resin, and mercapton to a homogeneous slurry, pouring the slurry into molds of desired geometric configuration, and allowing the slurry to cure.

United States Patent Turetsky et al.

[4 1 Feb. 19, 1974 PLASTIC BONDED FIRST FIRE Inventors: Abraham L. Turetsky, Bel Air;

Woodrow W. Reaves, Baltimore, both of Md.

The United States of America as represented by the Secretary of the Army, Washington, DC.

Filed: Nov. 3, 1970 Appl. No.: 86,450

Assignee:

US. Cl. 102/65 Int. Cl. F42b 27/00 Field of Search 102/64, 65; 149/83, 85

References Cited UNITED STATES PATENTS l/l933 Spring 102/65 2/1964 Anzalone 149/85 X Kristal 149/85 X Moore 149/83 Primary Examiner-Verlin R. Pendegrass Attorney, Agent, or Firm-Edward J. Kelly; Herbert Berl [5 7] ABSTRACT 5 Claims, 2 Drawing Figures PLASTIC BONDED FIRST FIRE DEDICATORY CLAUSE The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

Our invention relates to an improvement in the method of assembly and in the composition of the first fire, or starter, means for use in munitions, such as grenades; the first fire means being the structure which ignites the munition payload.

Starter means used in prior art munitions, such as used in U.S. Pat. Nos. 3,434,421 and RE 18938, required the starter mix to either be pressed into the munition or be poured into the munition as a volatile slurry. The pressing technique and use of volatile flammable solvents introduced hazardous assembly conditions, because these factors could lead to premature detonation of the munition while being assembled. Further, cracks sometimes formed in the prior art compacted starter mix upon jarring of the munition which caused munition malfunction and inoperability. Also, prior art starter mixes would not ignite if moisture were introduced into the completed munition through an imperfect seal. Moreover, burning factors of prior art starting mixtures could not be properly controlled as to quality which led to erratic burning performance. Our invention was conceived and reduced to practice to solve the above described problems and to satisfy the long felt need for a starter, or first fire, means which is not hazardous to assemble in munitions, can be uniformly reproduced, is not affected by the presence of moisture, and does not crack when subjected to rough handling and jarring.

A principal object of our invention is to provide a first fire means for munitions which is not hazardous to assemble into munitions.

Another object of our invention is to provide a first fire means for munitions which is not affected by moisture introduced into the assembled munition.

A further object of our invention is to provide a first fire means for munitions which can be uniformly reproduced.

A still further object of our invention is to provide a first fire means for munitions which is flexible and will not crack.

Other objects will be obvious from or will appear in the specification hereinafter set forth.

FIG. 1 is a top view of the munition shown in FIG. 2.

FIG. 2 is a view of a munition using our first fire means.

Our invention and FIGS. 1 and 2 will now be de scribed in detail as follows. The grenade shown at l is loaded with payload material 2, which can be any incendiary, explosive, smoke producing, or chemical agent material to suit a given application, and cup plate 3 is superimposed on the payload. Cup plate 3 contains a hole in the bottom thereof to permit ignition of the payload by the first fire means 4 inserted within the cup plate. First fire means 4 is ignited by conventional delay column 5 which is integral with conventional firing mechanism 6; firing mechanism 6 being fixedly mounted within cover means 7 in the conventional manner, such as threadably as shown in FIG. 2. Our improvement, first fire means 4, is a plastic bonded, flexible, rubbery, unit-constructed, waterproof subcombination which is merely placed within cup plate 3 and requires no pressing or use of flammable solvents to insert means 4 within munition 1. An exemplary composition for our first fire means 4 is set forth in the example below.

EXAMPLE Parts Viscosity Density Component by Weight at 25C at 25C Thioepoxy Resin 20:10 116 Poises 1.26 gm/cc Mercaptan 20:10 1.3 Poises 1.14 gm/cc Plasticizer 17:17 to 240 12.04 lb/gal Sec. Saybolt Acrawax C 0 to 10 Universal Potassium Chlorate 40:20 Sodium Bicarbonate 0 to 9 Each component listed in the above example is placed in a conventional blender and mixed until a homogeneous slurry is obtained. Sodium bicarbonate is utilized to decrease the amount of flame generated on ignition of the first fire means and to shorten the amount of time to cure the slurry. Acrawax C is utilized to reduce the first fire means impact sensitivity; the greater the amount of Acrawax C content, the lesser the impact sensitivity. After a homogeneous slurry is obtained, the slurry is poured into molds having a suitable configuration to suit a given application and permitted to cure in the conventional manner. The time and temperature for curing of the slurry depend on the particular resin, mercaptan, and plasticizer employed; particular components in the above example and amounts thereof being selectable and adjustable within the skill of the art to produce a flexible, rubbery, and waterproof first fire means. After the slurry has cured, the plastic bonded first fire means is assembled within munitions as above described. While a grenade is shown in the drawing, our invention can be utilized with any other munition application.

It is obvious that other modifications can be made of our invention, and we desire to be limited only by the scope of the appended claims.

We claim:

1. In a munition having a plurality of components comprising a firing mechanism, a delay column, a container means, and a payload, the improvement in combination with the components being a first fire means superimposed on the payload, the first fire means being a flexible, rubbery, waterproof structure comprising potassium chlorate, an oxidizing material, and a polymer which is the reaction product of a reaction between thioepoxy and mercaptan.

2. The munition of claim 1 wherein the thioepoxy resin is a material in an amount of 10 to 30 parts by weight and having a viscosity of 1 16 Poises at 25C and a density of 1.26 gm./cc. at 25C and the mercaptan is a material in an amount of 10 to 30 parts by weight and having a viscosity of 1.3 Poises at 25C and a density of 1.14 gm./cc.

3. The munition of claim 1 wherein the first fire means contains sodium bicarbonate.

4. The munition of claim 1 wherein the payload is a material selected from the group of materials consisting of incendiary material, chemical agent material, smoke producing material, and explosive material.

5. The munition of claim 1 wherein the munition is a grenade. 

2. The munition of claim 1 wherein the thioepoxy resin is a material in an amount of 10 to 30 parts by weight and having a viscosity of 116 Poises at 25*C and a density of 1.26 gm./cc. at 25*C and the mercaptan is a material in an amount of 10 to 30 parts by weight and having a viscosity of 1.3 Poises at 25*C and a density of 1.14 gm./cc.
 3. The munition of claim 1 wherein the first fire means contains sodium bicarbonate.
 4. The munition of claim 1 wherein the payload is a material selected from the group of materials consisting of incendiary material, chemical agent material, smoke producing material, and explosive material.
 5. The munition of claim 1 wherein the munition is a grenade. 